The approaches described in this section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Digitally stored electronic maps are used, for example, to provide directions to users of mobile or onboard computing devices, for example, using any of a wide array of standalone map or direction applications, programs, or apps. Today's digital map applications can correctly determine where a client device is (to an accuracy of a few feet or meters) and show in real time where the client device is located on a digital map. Digital map applications also typically include other functionality, such as providing turn-by-turn directions from the client device's current location to nearly any other location. Additional elements such as traffic conditions, accidents, or other notable events may also be displayed on a digital map.
Digital maps also can be found in other applications aside from standalone map applications. For example, ride sharing applications, taxi applications, video games, and many other types of applications may use digital maps. These or other applications can obtain digital maps for display by calling a mapping server through an Application Programming Interface (API). Thus, a single digital map provider that owns or operates the mapping server may supply the digital maps for many different apps with disparate functionality.
In digital map systems, the location of a client device can be determined using WiFi or the Global Positioning System (GPS), which reports a device's location using latitude and longitude, and optionally elevation and time as well. This location data, as well as other data, typically is collected by the digital map provider. In some cases, the collected location data is extremely detailed, recording precise the locations, times, and patterns of movement of the client device.
However, individual end users typically own or control the client devices that provide location data to a digital map provider. For example a user's smartphone can be a client device, and the collected location data from the smartphone can be extrapolated to determine the habits and identity of the end user (for example, determining a home address and a work address of the user). Similarly, location data may be accompanied by metadata directly identifying the associated client device or user. However, end users may not want their locations, routes, or other movement information to be known to the digital map provider, to become public, or to be acquired by a government without their permission. In order to maintain user privacy, it is important to anonymize stored location data such that the location data is not traceable to particular users. However, currently available methods for anonymizing location data may merely remove direct metadata associations between the individual user and the location data. Despite the use of these existing methods, in many cases a user's identity can be accurately inferred through analysis of location data alone. Thus, improved methods for anonymizing location data are needed.